Air heat exchanger

ABSTRACT

The present disclosure relates to an air heat exchanger in air diffuser systems with flexible planar heat exchanger elements, in particular for use in aircraft. In accordance with the present disclosure, the individual planar heat exchanger elements are connected with each other by means of webs. The present disclosure furthermore relates to a method for manufacturing air heat exchangers as well as to a use thereof.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application Serial No.10 2005 018 050.7 filed Apr. 19, 2005, which is hereby incorporated byreference in its entirety for all purposes.

FIELD

The present disclosure relates to an air heat exchanger in air diffusersystems with flexible planar heat exchanger elements, in particular foruse in aircraft.

BACKGROUND AND SUMMARY

For heating the air, heaters are incorporated in air diffuser systems.For safety reasons, heating elements with high surface temperatures areundesirable in the aircraft industry. Therefore, so-called panel heatingelements are being used. Due to their large surface area, the same arecapable of transferring a high thermal power despite low temperatures.The objective is to install a rather large surface area on a smallspace, in order to be able to transfer as much heat as possible. Outputof the thermal power should be effected in a controlled way, andinadmissible excess temperatures should be avoided. This is ensured bythe use of sensors and fuses. Therefore, the elements should beproducible at low cost and should achieve a rather high performance witha low weight and a small size.

Air heaters with a structure as shown in the attached FIG. 1 are knownalready. In an air-conducting tube 12 to be heated, flexible panelheating elements 10 are inserted, which in the illustrated embodimentare arranged parallel to each other. In this case, the panel heatingelements constitute free-standing plates. As an alternative to theillustrated embodiment, the panel heating elements can also consist ofcoaxially arranged tubes. There can also be provided heat-dissipatingcooling bodies, for instance in the form of heat exchanger lamellae.

These prior art systems involve a very high contacting effort, as theindividual panel heating elements must be connected with each other viasoldering points, plug-in connections and the like. As a result, therisk of defects is substantially increased during the manufacture ofsuch elements. In particular the manufacture of coaxial panel heatingelements involves a substantially higher mounting effort as compared toplate-shaped elements.

It is the object of the present disclosure to create an air heatexchanger which is comparatively easier to manufacture and to install.

In accordance with the present disclosure, this object is solved by anair heat exchanger in an air diffuser system comprising flexible planarheat exchanger elements, in particular for use in aircraft, wherein theindividual planar heat exchanger elements are connected with each otherby means of webs.

In one example, these webs themselves are unheated. Inside these webs,conductors are disposed, which connect the individual heat exchangerconductors in the individual surfaces with each other. The webs onlyserve the mechanical connection of the planar heat exchanger elements.The corresponding conductors usually, but not necessarily, are electricconductors.

Accordingly, the planar heat exchanger elements can have a variabledesign in terms of shape, size and heat exchanger performance. Thus,they can result in a much better utilization of the flow cross-sectionof the air-conducting conduit. In certain portions of round tubes, forinstance, flow can be greater, so that they can provide a greater heatexchanger performance.

To effect a uniform surface temperature of the flexible heat exchangerelements in the direction of the traversed length, the same can also beequipped with a variable power density along their length. With aspecified maximum temperature, which should not be exceeded, a uniformtemperature can thus be adjusted along the length of the tube.

Particularly advantageously, additional heat exchanging bodies areprovided, for instance plates and/or ribs. The additional heatexchanging bodies can be used both as supports and as spacers for theplanar heat exchanger elements.

The above-mentioned object of the present disclosure is solved inparticular by a method wherein, the planar heat exchanger elements aremanufactured together with the webs connecting the same as an integralelement.

Accordingly, the sensors or other fuses for monitoring the temperatureas well as connecting lines leading to the same can be integrated rightduring the manufacturing process of the planar heat exchanger elementsand the webs connecting the same.

Upon manufacture of the planar heat exchanger elements and the webs ofeach element, the same is bent into its final shape. As far as the heatexchanger element is incorporated in a pipe conduit, the same willafterwards be inserted into the pipe conduit. In accordance with theherein disclosed aspect of the air heat exchanger, it is no longernecessary to connect each individual planar heat exchanger elementseparately. Rather, it is sufficient to connect the entire planar heatexchanger element to the heat exchanger fluid conduit.

Particularly advantageously, the aforementioned air heat exchanger isused as an air heater, preferably for use in aircraft.

Further details, features and advantages of the present disclosure willbe illustrated with reference to an embodiment shown in the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a partly sectioned air heat exchanger in accordance withthe prior art; and

FIG. 2 shows several views of a part of an air heat exchanger in variousstructural conditions in accordance with the present invention.

DETAILED DESCRIPTION

In FIGS. 2 a to 2 c, the various manufacturing steps of an air heatexchanger 20 are shown. The same first of all consists of a number ofplanar heat exchanger elements 10, which are each connected with eachother by means of webs 14. The webs 14 substantially have the samestructure as the heat exchanger elements 10, which in the presentembodiment constitute panel heating elements. Instead of correspondingpanel heating elements, the same can of course also constitute panelcooling elements when used in an air conditioning system.

In a manner not illustrated here, the webs include unheated conductors,which connect the heating conductors of the individual flexible heatexchanger elements 10. In principle, the unheated webs 14 have the samestructure as the individual flexible heating elements 10, whereby theycan be manufactured in one and the same work process. This allowssimultaneous manufacture of a plurality of flexible heating elements 10together with the necessary unheated webs 14 in the same process. Afterthe manufacturing process in flat position, as shown in FIG. 2 a, theheat exchanger elements 10 are bent around the respective webs 14, as isshown in FIG. 2 b. This results in a stack of planar heat exchangerelements, which can for instance be inserted in a pipe conduit.

Advantageously, the planar heat exchanger elements 10 each can have adifferent width, which is not illustrated here in greater detail. As aresult, they are adapted better to the interior of the pipe. As is forinstance indicated in FIG. 2 c, the flexible planar heat exchangerelements 10 can be connected with heat exchanging bodies 16, whichdissipate the heat through convection to the surrounding medium, e.g.air. In addition, there can also be provided heat exchanging ribs, whichcannot be seen in FIG. 2 c. The cooling bodies, in particular in theform of ribs, can at the same time be used as supports for the flexibleplanar heat exchanger elements. This provides for a very compactconstruction.

1. An air heat exchanger in air diffuser systems, comprising flexibleplanar heat exchanger elements, wherein the individual planar heatexchanger elements are connected with each other by means of webs. 2.The air heat exchanger as claimed in claim 1, wherein the air heatexchanger is coupled in an aircraft.
 3. The air heat exchanger asclaimed in claim 1, wherein the webs are made of a flexible, bendablematerial.
 4. The air heat exchanger as claimed in claim 1, wherein thewebs have a structure that is the same as the planar heat exchangerelements.
 5. The air heat exchanger as claimed in claim 1, wherein theplanar heat exchanger elements have a variable design in terms of shape,size and heat exchanger performance.
 6. The air heat exchanger asclaimed in claim 1, wherein the planar heat exchanger elements have avariable heat exchanger performance along their length, in order toachieve a uniform surface temperature in the direction of the traversedlength.
 7. The air heat exchanger as claimed in claim 1, wherein theplanar heat exchanger elements are connected with additional heatexchanging bodies.
 8. The air heat exchanger as claimed in claim 7,wherein the additional heat exchanging bodies are shaped in a form ofplates and/or ribs.
 9. The air heat exchanger as claimed in claim 1,wherein the planar heat exchanger elements constitute plates.
 10. Theair heat exchanger as claimed in claim 1, wherein the additional heatexchanging bodies are used as supports and as spacers for the planarheat exchanger elements.
 11. A method for manufacturing an air heatexchanger in air diffuser systems comprising fabricating a plurality ofindividual planar heat exchanger elements and a plurality of websconnecting the individual planar heat exchanger elements as an integralelement.
 12. The method as claimed in claim 11, wherein sensors formonitoring the temperature as well as their connecting lines areintegrated into the planar heat exchanger elements during thefabricating process.
 13. The method as claimed in claim 11, wherein theplanar heat exchanger elements are first manufactured in a flat positiontogether with the webs connecting the same and are then bent into afinal shape and possibly inserted into a pipe conduit.
 14. The method asclaimed in claim 11, further comprising using said air heat exchanger asan air heater to heat air in an aircraft.
 15. The method as claimed inclaim 11, wherein said individual planar elements are flexible.
 16. Anair heat exchanger in air diffuser systems, comprising: a plurality offlexible planar heat exchanger elements, and a plurality of websconnecting the individual planar heat exchanger elements, wherein theair heat exchanged is coupled in an aircraft.
 17. The air heat exchangeras claimed in claim 16, wherein the webs are made of a flexible andbendable material, and wherein the webs have a structure that is thesame as the planar heat exchanger elements.
 18. The air heat exchangeras claimed in claim 16, wherein at least two planar heat exchangerelements have a variable shape, size and heat exchanger performance. 19.The air heat exchanger as claimed in claim 18, wherein at least twoplanar heat exchanger elements have a variable heat exchangerperformance along their respective lengths, in order to achieve auniform surface temperature in the direction of the traversed length.20. The air heat exchanger as claimed in claim 19, wherein at least oneplanar heat exchanger element and one web are integrally formed, theexchanger further comprising a plurality of sensors for monitoring thetemperature as well as corresponding connecting lines, said sensorsfurther being integrally formed into the planar heat exchanger elements.